Don...I may be wrong, but I think some hunters were driving along (a dirt road?) when the earthquake ruptured ahead of them and a wall formed (the scarp) and they had to stop suddenly. This was a normal fault earthquake. It is expected that the mountain will go up (the footwall) AND the valley will go down (the hanging-wall). That is why the mountains are there. The hanging-wall goes down because it drops down the fault. The footwall goes up because the load of the hanging wall is removed partly from it. Or, another way to look at it is to read my recent post to Cathyryn about flexing the fault...when it snaps one side moved up and the other moves down.
You can say the same thing about San Andreas earthquake...which side moved depends on your reference frame....but it is really both sides.
Chris